Learned imitation cross-species behavior in Toronto
http://www.alansondheim.org/rockdovegull.mp4
Observe the pigeon behavior; there's too little (thrown)
food, and too many pigeons = competition. The new
behavior - I was barely able to capture it - is that of
a pigeon (rock dove) spreading its wings to look fierce
and mobbing the others. We have never seen this behavior
in New York, and we're veteran bird culture observers.
Note that ring-billed gulls enter the picture and use the
same technique; while it may be common among them, we
haven't seen this either. The conclusion is that once
species learned it from the other - probably the pigeon
from the gull. It was fascinating to watch; while I was
videoing, the food source, an older man, walked away, and
the event was over.
(Shot on the University of Toronto campus.)